Steve French [off-list ref] writes:

quoted

Or we could decide that cifs in initrd is not supported?

Paulo had been experimenting with booting from cifs.ko (over SMB3.11
mounts to Samba).

Presumably since SMB3/SMB3.11 family of protocols is the most common
network file system across a pretty broad variety of operating systems
it is easier to imagine it being extended for special cases like
booting the OS (it is already very feature rich compared to most
network/cluster file system protocols and has exhaustive detailed
documentation).

My gut reaction is that if cifs.ko (SMB3.11 mounts) don't work with
initrd ... we need to fix that even if it means minor protocol
extensions, but Paulo might have more data.

I was able to boot a Leap 15 system from cifs.ko with changes in [1], so
IMHO, it would probably make sense to support cifs in initrd as well --
though I haven't tested it myself.

Thanks,
Paulo

[1] https://git.paulo.ac/linux.git/commit/?h=smb-boot